Polyamide water-treatment separation membrane having properties of high salt rejection and high flux and manufacturing method thereof

Abstract

The present disclosure provides a method of manufacturing a water-treatment separation membrane having improved salt rejection rate and permeable flux properties, the method including: forming an aqueous solution layer containing an amine compound on a porous support; forming a polyamide active layer by bringing an organic solution containing an acyl halide compound and a first organic solvent into contact with the aqueous solution layer; and coating a second organic solvent having a degree of volatility lower than that of the first organic solvent on the polyamide active layer, and a water-treatment separation membrane manufactured by the manufacturing method.

1 . A method of manufacturing a water-treatment separation membrane, the method comprising:
 forming an aqueous solution layer containing an amine compound on a porous support;   forming a polyamide active layer by bringing an organic solution containing an acyl halide compound and a first organic solvent into contact with the aqueous solution layer; and   coating a second organic solvent having a degree of volatility lower than that of the first organic solvent on the polyamide active layer.   
     
     
         2 . The method of  claim 1 , wherein the coating of the second organic solvent on the polyamide active layer includes forming a polyamide through an additional interfacial polymerization reaction between residual portions of the acyl halide compound and the amine compound remaining on the polyamide active layer. 
     
     
         3 . The method of  claim 1 , wherein the first and second organic solvents are nonpolar solvents. 
     
     
         4 . The method of  claim 1 , wherein a vapor pressure of the first organic solvent at 20° C. is 5 kPa to 60 kPa, and a vapor pressure of the second organic solvent at 20° C. is 0.05 kPa to 1.5 kPa. 
     
     
         5 . The method of  claim 1 , wherein the first organic solvent is a hydrocarbon solvent having 5 to 7 carbon number, and the second organic solvent is a hydrocarbon solvent having 8 to 15 carbon number. 
     
     
         6 . The method of  claim 1 , wherein the first organic solvent is at least one selected from a group consisting of pentane, hexane, and heptane, and the second organic solvent includes at least one selected from a group consisting of octane, nonane, decane, undecane, dodecane and an isoparaffin solvent, a mixture of alkanes having 8 to 15 carbon number. 
     
     
         7 . A water-treatment separation membrane comprising:
 a porous support; and   a polyamide active layer formed on the porous support,   wherein the polyamide active layer is formed by forming an aqueous solution layer containing an amine compound on the porous support, bringing an organic solution containing an acyl halide compound and a first organic solvent into contact with the aqueous solution layer, and then, coating a second organic solvent having a degree of volatility lower than that of the first organic solvent.   
     
     
         8 . The water-treatment separation membrane of  claim 7 , wherein a vapor pressure of the first organic solvent at 20° C. is 5 kPa to 60 kPa, and a vapor pressure of the second organic solvent at 20° C. is 0.05 kPa to 1.5 kPa. 
     
     
         9 . The water-treatment separation membrane of  claim 7 , wherein the first organic solvent is a hydrocarbon solvent having 5 to 7 carbon number, and the second organic solvent is a hydrocarbon solvent having 8 to 15 carbon number. 
     
     
         10 . The water-treatment separation membrane of  claim 7 , wherein the first organic solvent is at least one selected from a group consisting of pentane, hexane, and heptane, and the second organic solvent includes at least one selected from a group consisting of octane, nonane, decane, undecane, dodecane and an isoparaffin solvent, a mixture of alkanes having 8 to 15 carbon number. 
     
     
         11 . The water-treatment separation membrane of  claim 7 , wherein in a case in which a sodium chloride (NaCl) solution at a concentration of 32,000 ppm permeates through the water-treatment separation membrane under pressure conditions of 800 psi, the water-treatment separation membrane has an initial salt rejection rate of 99.00% or more and an initial permeable flux of 34 to 40 gallons/ft 2 ·day. 
     
     
         12 . The water-treatment separation membrane of  claim 7 , wherein after an aqueous sodium hypochlorite (NaOCl) solution at a concentration of 2,000 ppm permeates through the water-treatment separation membrane for 12 hours, the water-treatment separation membrane has a salt rejection rate of 98.00% or more and a permeable flux of 32 to 40 gallons/ft 2 ·day. 
     
     
         13 . The water-treatment separation membrane of  claim 7 , wherein a thickness of the polyamide active layer is 110 to 180 nm. 
     
     
         14 . A water-treatment module comprising the water-treatment separation membrane of  claim 7 . 
     
     
         15 . A water-treatment device comprising the water-treatment module of  claim 14 .